Emergency shutoff valve for use in a fuel dispensing system

ABSTRACT

An emergency shutoff valve is provided that includes a housing defining a fluid inlet, a fluid outlet and a fluid flow passage extending therebetween. The valve includes a valve element disposed within the housing and releasably latched in an open position by a latching mechanism. An expansible member defines at least a portion of a sealed expansible chamber that is sealed at locations downstream and upstream of a weakened portion of the housing. The valve includes an access port in fluid communication with the chamber. The access port may be used to test the integrity of the expansible member. An expandable material may also be disposed in the chamber and used to shut off the valve on the occasion the housing is compromised to an extent wherein fuel can flow into the expansible chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.11/553,067 filed on Oct. 26, 2006, the disclosure of which is expresslyincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to valves, and more particularlyto emergency shutoff valves for use in fuel dispensing systems.

BACKGROUND

Fuel dispensing systems used at retail gas stations typically include anunderground tank containing gasoline, diesel fuel or other liquid fuels,an above ground dispensing unit terminating in a nozzle adapted tosupply the fuel to a motor vehicle, and a piping system interconnectingthe underground tank and dispensing unit. While infrequent, vehicles cancollide with the dispensing unit, causing the dispensing unit to bedisplaced. It is also possible for the unit to be displaced due tocertain environmental conditions. In either event, a fuel pipe orconduit may rupture, causing fuel to be spilled and creating apotentially hazardous condition, unless preventive measures are taken.

A variety of emergency fuel shutoff valves are known in the art thathave been developed in response to the foregoing potential problem.Known valves of this type include those having upper and lower housingsreleasably connected to one another, with the lower housing rigidlymounted. For instance, the lower housing can be mounted within a sumplocated beneath a concrete pedestal supporting the dispensing unitusing, for example, a mounting bar as is known in the art. The lowerhousing is operably connected to the underground tank via undergroundconduits, while the upper housing is operably connected to the fueldispensing unit.

A weakened portion, such as a circumferential groove, formed in theupper housing provides a planned failure site so that a first portion ofthe valve can separate from a second portion of the valve when one ofthe first or second portions is subjected to a predetermined load. Sucha separation of valve portions causes a valve element in the lowerhousing to move from a releasably latched open position to a closedposition, shutting off the flow of fuel from the underground tank.Shutoff valves of this type may also include a check valve in the upperhousing that closes under the action of a biasing member when the valveportions separate. The check valve may reduce or prevent the backflow offuel from the dispensing unit.

Emergency shutoff valves of the foregoing type have been successfullyused in fuel dispensing systems, but they can exhibit certaindisadvantages. For instance, it is possible even though highly unlikelyfor the dispensing unit to be subjected with a load or force that is notsufficient for the first portion of the shutoff valve to be separatedfrom the second portion of the valve, but is sufficient to compromisethe structural integrity of the valve housing. In other words, a loadmay in a very unusual situation crack the valve housing along the groovewithout completely separating the valve portions on either side of thegroove. In this event, the valve element in the lower housing may notclose, which may permit fuel to escape from the housing through thecracked or otherwise damaged weakened portion of the valve, resulting inundesirable spillage of fuel to the environment.

It is therefore desirable to provide an emergency shutoff valve for usein fuel dispensing systems that overcomes the disadvantages associatedwith known emergency shutoff valves.

SUMMARY

To these ends, an embodiment of the invention contemplates an emergencyshutoff valve having a frangible, or weakened portion or other form ofpredetermined failure area disposed within or forming a portion of anexpansible chamber. Any leak from this frangible area, such as mightoccur from an impact to a fuel dispenser or due to certain environmentalconditions, actuates a movable member which defines at least a portionof an expansible chamber, and this movement is operatively coupled tothe valve so as to cause it to shut off. Accordingly, fuel leaks fromimpact or valve trauma less than full valve compromise, i.e., crackingthe valve without fully shearing or separating the valve, may becontained or reduced through valve shut off.

More particularly, an emergency shutoff valve according to oneembodiment of the invention is provided for use in a fuel dispensingsystem. The emergency shutoff valve comprises a housing defining a fluidinlet, a fluid outlet and a fluid flow passage extending between thefluid inlet and the fluid outlet. The flow passage may be suitable forthe flow of fuel therein. The valve may further include a valve elementmovable within the housing between an open position, in which fuel ispermitted to flow between the fluid inlet and outlet, and a closedposition, in which fuel is prevented from flowing between the fluidinlet to the fluid outlet. A latching mechanism may be coupled to thevalve element and the housing to releasably latch the valve element inthe open position. The valve may also include an expansible memberdefining at least a portion of a sealed expansible chamber external ofthe housing. The housing comprises a weakened portion downstream of thevalve element and the expansible chamber is sealed to the housing at afirst location upstream of the weakened portion and at a second locationdownstream of the weakened portion so as to bound or enclose theweakened portion. The emergency shutoff valve defines a failure modewherein the structural integrity of the housing is compromised to anextent wherein fuel may escape from the housing through a crack in theweakened portion and into the expansible chamber when a predeterminedload is applied to the housing. Upon occurrence of the failure mode, theexpansible member is operable for uncoupling the latching mechanism fromat least one of the housing and the valve element, wherein the valveelement moves from the open position to the closed position to stop theflow of fuel through the valve. In particular, the pressure in the fuelline causes fuel to flow into the expansion chamber through the crack inthe weakened portion of the housing so as to actuate the expansiblemember thereby causing the valve element to move to the closed position.

In other embodiments, the emergency fuel shutoff valve may include oneor more of the following features. In some embodiments, the expansiblemember may comprise a sleeve, made of an elastomeric material, disposedin surrounding relationship with the housing. The valve further mayinclude a rotatable shaft having one end projecting outwardly from thehousing, with the valve element being coupled to the shaft for rotationtherewith. A biasing member cooperates with the shaft to bias the valveelement toward the closed position.

The latching mechanism may be a linkage. In one embodiment, the linkageincludes first and second links, each having proximal and distal ends,with the proximal end of the first link being coupled to the housing andthe distal end of the first link being coupled to the proximal end ofthe second link. The distal end of the second link may be coupled to theend of the rotatable shaft that projects outwardly from the housing. Inthis embodiment, the expansible member is operable for contacting andmoving the first link upon occurrence of the failure mode, wherein thefirst link is uncoupled from one of the housing and the second link, andwherein the valve element is unlatched and moves from the open positionto the closed position. The first link may include a protruding portiondisposed between the proximal and distal ends of the first link andprotruding toward the expansible member.

Alternatively, the first link may include a first link portion and asecond link portion each pivotally coupled to the housing. The firstlink portion may include a notch and the second link portion may includea first, second and third arm. The proximal end of the second link mayinclude a pin that is received in the notch of the first link portionwhen the valve element is releasably latched in the open position. Thedistal end of the second link may be coupled to the end of the rotatableshaft that projects outwardly from the housing. The second arm of thesecond link portion may extend generally tangentially relative to thehousing proximate the expansible member. In this embodiment, theexpansible member is operable, upon occurrence of the failure mode, forcontacting the second arm, causing the first link to rotate and the pinto become disengaged from the notch in the first link portion, whereinthe valve element is unlatched from the open position and moves to theclosed position.

In another embodiment, the valve may further comprise an annular memberat least partially circumscribing the housing and a hollow protrudingmember integral with the annular member and extending away from thehousing. In this embodiment, the expansible member may comprise adiaphragm made of an elastomeric material and the expansible member canbe disposed in sealing engagement with the protruding member. Thelinkage may comprise first and second links coupled to one another. Thefirst link may be coupled to the housing at its proximal end and coupledto the proximal end of the second link at its distal end. The distal endof the second link may be coupled to the end of the rotatable shaft thatprojects outwardly from the housing. In this embodiment, the expansiblemember is operable for contacting and moving the first link uponoccurrence of the failure mode wherein the first link is uncoupled fromone of the housing and the second link, and the valve element isunlatched and moves from the open position to the closed position.

The weakened portion of the housing may take a variety of forms. In oneembodiment, it is a circumferential groove. At least a portion of thegroove can be generally V-shaped. The expansible member may be made ofany suitable material, including those selected from the groupconsisting of fluro silicone rubber, BUNA-N rubber, fluro elastomerrubber or other suitable materials.

The housing preferably includes a lower housing and an upper housingsecured to one another, with the lower housing adapted to be mountedwithin a sump beneath a dispensing unit and further adapted to beoperatively coupled to a source of pressurized fuel. The upper housingpreferably includes the weakened portion and may be adapted to becoupled to a fuel pipe within the dispensing unit. The valve element ispreferably disposed within the lower housing, upstream of the weakenedor frangible portion of the valve.

The emergency shutoff valve may further include a normally open, secondvalve element disposed within the upper housing and a biasing memberbiasing the second valve element toward a closed position.

The embodiments of the shutoff valve may include an access port havingan inlet, outlet, and an open channel extending therebetween. The outletis in fluid communication with the expansible chamber. Such an accessport may be used to test the integrity of the expansible member. Theaccess port may further provide some advantages during assembly of theshutoff valves.

Furthermore, embodiments of the shutoff valve include an expandablematerial disposed in the expansible chamber. The expandable material hasa first volume when dry but expands to a second volume greater than thefirst volume when it comes into contact with a liquid, such as fuel. Theexpandable material may be used alone or in combination with the fluidconduit line pressure as the motive force for shutting the valve on theoccasion of leaking fuel.

According to another aspect of the invention, a method is provided forisolating a leak in a fuel dispensing system. The method comprisesproviding an emergency shutoff valve for use in the fuel dispensingsystem, with the valve comprising a housing with a weakened portiontherein, and the housing defining a fluid inlet, a fluid outlet and afluid flow passage therebetween. The valve further comprises a valveelement movable between an open position and a closed position. Themethod further comprises providing a linkage coupled to the valveelement and the housing, wherein the linkage releasably latches thevalve element in the open position. Additionally, the method comprisesdefining at least a portion of an expansible chamber with an expansiblemember sealed to the housing at locations upstream and downstream of theweakened portion, wherein the expansible member is operable, uponoccurrence of a fuel leak from the fluid flow passage through theweakened portion and into the expansible chamber, for uncoupling thelinkage from at least one of the housing and the valve element, whereinthe valve element is unlatched and moves from the open position to theclosed position to stop the flow of fuel through the valve.

Stated in another way, the method comprises the steps of defining afrangible area in a fluid conduit downstream of a cut-off valve, anddisposed within an expansible chamber sealed to the conduit downstreamand upstream of the frangible area, and closing the valve upon movementof an expansible member forming at least a portion of the expansiblechamber in response to leakage of the fluid through the frangible area.In one aspect of the invention, the pressure in the fuel line issufficient to actuate the expansible member so as to close the valvewhen a leak occurs along the weakened or frangible area.

A method is also provided for testing an emergency shutoff valve byproviding a valve having a housing with a weakened portion therein, anexpansible member at least partially surrounding the weakened portion todefine an expansible chamber therebetween, and an access port in fluidcommunication with the expansible chamber. The method further comprisespressurizing the expansible chamber and monitoring the pressure therein.If the pressure changes more than a specified threshold value, then theexpansible member may be changed.

Yet another method is provided for shutting off fuel through a conduitdefining a frangible area therein and includes defining a chamber aboutthe frangible area with an expansible member forming at least a portionof the chamber, disposing an expandable material in the chamber, andusing the expansion of the expandable material to shut off fuel flowthrough the conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims and accompanying drawings wherein:

FIG. 1 is a schematic illustration of a fuel dispensing system thatincorporates an emergency shutoff valve according to an embodiment ofthe present invention;

FIG. 2 is a perspective view of the emergency shutoff valve shownschematically in FIG. 1;

FIG. 3A is a cross-sectional view taken along line 3A-3A in FIG. 2, witha valve included in the lower housing shown in an open position;

FIG. 3B is a cross-sectional view similar to FIG. 3A, but with a failuremode associated with a weakened portion of the emergency shutoff valveillustrated;

FIG. 3C is a cross-sectional view similar to FIGS. 3A and 3B, furtherillustrating the failure mode shown in FIG. 3B;

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2;

FIG. 5 is a perspective view of an emergency shutoff valve according toanother embodiment of the present invention;

FIG. 6A is a cross-sectional view taken along line 6A-6A in FIG. 5illustrating the included linkage of the shutoff valve in a positionthat latches a valve element (not shown in FIG. 6A) in the lower housingin an open position;

FIG. 6B is a cross-sectional view similar to FIG. 6A, but with theincluded linkage in a position that unlatches the valve element in thelower housing (not shown in FIG. 6B), allowing it to move to a closedposition;

FIG. 7 is a perspective view of an emergency shutoff valve according toanother embodiment of the present invention;

FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7;

FIG. 9 is a cross-sectional view of an emergency shutoff valve accordingto another embodiment of the present invention;

FIG. 10A is a cross-sectional view of an emergency shutoff valveaccording to yet another embodiment of the present invention; and

FIG. 10B is a cross-sectional view similar to FIG. 10A, but with afailure mode associated with a weakened portion of the emergency shutoffvalve illustrated.

DETAILED DESCRIPTION

FIG. 1 is a schematic illustration of a fuel dispensing system 10 thatincorporates an emergency shutoff valve 20 according to the presentinvention. The fuel dispensing system 10 includes a source of fuel 22having fuel 24 contained therein. As shown in FIG. 1, the source 22 offuel may be an underground fuel tank, such as that used at a retail gasstation for instance. The fuel dispensing system 10 may further includea stand pipe extending into the fuel tank, a sump 26, various flowcontrol and flow measurement devices (not shown) and a section of piping28 that is mechanically and fluidicly coupled to valve 20. Valve 20comprises a housing, or fluid conduit, 30 that may include first 32 andsecond 34 housings that are removably secured to one another byconventional means, such as fasteners 36 shown in FIG. 2. While thepreferred embodiment described herein includes two separate housings 32,34 coupled together, the invention is not so limited as the valve 20 mayhave a one-piece housing. The two-piece structure allows the secondhousing 34 (which has the shear groove) to be replaced without alsoreplacing the first housing 32. In the illustrated embodiment, the firsthousing 32 is a lower housing and the second housing 34 is an upperhousing. The terms upper and lower are used to describe embodiments andto facilitate understanding of the invention and does not limit theinvention to a certain orientation. Fuel system 10 may further include afuel dispensing unit 38 that may be mounted on a pedestal 40, which maybe made of concrete and which in turn may be mounted on a surface, suchas, for example, a concrete surface of a retail gas station. The lowerhousing 32 may be rigidly mounted within a sump 41 below or adjacent thepedestal 40.

The fuel dispensing system 10 may further include a rigid pipe orconduit 42 that may extend upwardly through the interior of thedispensing unit 38. Pipe 42 may be mechanically coupled, at a lower end,to the upper housing 34 of valve 20 and is in fluid communication withvalve 20. Pipe 42 may also be in fluid communication with a flexiblehose 44 that terminates in a nozzle 46 that is adapted for dispensingfuel into the fuel tank of a motor vehicle, such as an automobile,truck, etc.

Referring now to FIGS. 2-4, housing 30 of valve 20 generally defines afluid inlet 50, a fluid outlet 52 and a fluid flow passage 54 extendingbetween the fluid inlet 50 and the fluid outlet 52. The fluid flowpassage 54 may be suitable for the flow of pressurized fuel therein,such as fuel 24. The fuel 24 may be pressurized by a pump (not shown)included in the fuel dispensing system 10.

Valve 20 includes a valve member 60 that may be a flapper or butterflytype valve and which may be movably mounted within the lower housing 32.Valve member 60 includes a valve element 62 that is movable between anopen position shown in FIGS. 3A, 3B and in solid line in FIG. 4, and aclosed position shown in FIG. 3C and in phantom line in FIG. 4. In theclosed position, the valve element 62, such as a sealing disk, may bedisposed in sealing engagement with a valve seat 64 and is adapted tocut off or prevent fuel flow from the fluid inlet 50 to the fluid outlet52. The valve element 62 may be supported by a structure, indicatedgenerally at 66. Additional details of the structure 66 that can be usedare found in U.S. Pat. Nos. 5,454,394; 5,193,569; and 5,099,870 thatdisclose conventional shear valves. Each of these patents is assigned tothe assignee of the present invention and is expressly incorporated byreference herein in its entirety. The support structure 66 may include apair of arms 68 having square openings that are received by a squaresection of a rotatable shaft 70, such that the valve element 62 andsupporting structure 66 rotate with shaft 70. Valve element 62 andsupporting structure 66 may be biased toward the closed position by abiasing member 72, which can be a torsion spring, coiled about the shaft70. However, the valve element 62 and associated support structure 66may be releasably latched in the open position by a latching mechanismindicated generally at 74 in FIG. 2. In the illustrated embodiment,latching mechanism 74 may be a linkage. However, latching mechanism 74may be other devices suitable for releasably latching valve element 62in the open position. During normal operation of valve 20, i.e., notduring a failure mode of valve 20, the linkage 74 may be coupled to boththe valve element 62 and to housing 30 as explained in more detailbelow.

Linkage 74 may include a first link 76 having a proximal end 78 coupledto housing 30. In the illustrated embodiment, this is accomplished by apin 80 secured at one end to housing 30 and having an opposite endextending through an aperture formed in the proximal end 78 of firstlink 76. First link 76 further includes a distal end 82 that is coupledto a proximal end 84 of a second link 86 of linkage 74. A distal end 88of second link 86 may be coupled to an end 90 (FIG. 3A) of the rotatableshaft 70 that projects outwardly from the housing 30. First link 76 mayalso include a protruding portion 92 that is disposed between theproximal 78 and distal 82 ends of first link 76 and is used for asubsequently discussed purpose.

The outer end 90 of the rotatable shaft 70 may include a cylindricalportion and the distal end 88 of second link 86 may include a circularaperture formed therein that engages the cylindrical portion of theouter end 90 of shaft 70. The distal end 88 of second link 86 may besecured to the outer end 90 of shaft 70 by soldering for instance, withthe solder having a relatively low melting point. Accordingly, in theevent of a fire surrounding valve 20, the solder can melt, allowingshaft 70 to rotate within second link 86, thereby causing the valveelement 62 and supporting structure 66 to move from the open positionshown in FIGS. 3A and 3B and in solid line in FIG. 4, to the closedposition shown in FIG. 3C and in phantom line in FIG. 4, under theaction of the biasing member 72. Alternatively, and in accordance withanother embodiment of the invention, instead of the distal end 88 of thesecond link 86 being configured as a fusible hub that releases the valveelement 62 in the event of a fire, as is conventional, the first link 76may include a fusible section intermediate the proximal and distal ends78, 82. Thus, in the event of a fire, the fusible section meltsseparating the end 78, 82 of the first link 76 and allowing the valveelement 62 and supporting structure 66 to move to the closed positionunder the action of biasing member 72. Implementing the fusible sectionin the first link 76 may provide certain cost and manufacturingadvantages as compared to the traditional placement of a fusible sectionin the distal end 88 of the second link 86.

Housing 30 includes a weakened, or frangible, portion 94 formed thereinthat is downstream of valve member 60. In the illustrated embodiment,upper housing 34 includes the weakened portion 94 formed therein, whichextends circumferentially around a perimeter of the upper housing 34.The invention, however, is not so limited. The weakened portion 94 maybe a groove and can have an inner portion 96 that is generally V-shaped,as shown in the illustrated embodiment. The invention is not so limitedas those of ordinary skill in the art will recognize otherconfigurations that define the weakened portion 94. The weakened portion94 defines a predetermined fracture of failure site for various failuremodes as subsequently discussed.

In an exemplary embodiment, valve 20 may further include an expansiblemember 100. The expansible member 100 may be a sleeve disposed insurrounding relationship with the weakened portion 94, as shown in theillustrated embodiment, and member 100 may be made of an elastomericmaterial. Suitable materials include fluro silicone rubber, BUNA-Nrubber and fluro elastomer rubber. However, other materials may be usedprovided they exhibit sufficient resistance to ozone, to prevent dryrot, and are resistant to fuel corrosion. The expansible member 100generally surrounds the weakened portion 94 and may be sealed to theupper housing 34 at a first location 102 upstream of the weakenedportion 94 and at a second location 104 downstream of the weakenedportion 94 so as to bound or encompass weakened portion 94. Theexpansible member 100 may be sealed to the upper housing 34 by a pair ofband clamps 106 that extend around the perimeter of upper housing 34 orother suitable devices such as straps and the like. The expansiblemember 100 defines at least in part an expansible chamber 108 best seenin FIGS. 3B and 3C. The function of the expansible member 100 issubsequently discussed.

Valve 20 may optionally include a second valve member 110 disposedwithin the upper housing 34 of valve 20, downstream of the weakenedportion 94. Valve member 110 may, for example, be a spring loaded poppetor check valve having a valve element 112 that may be a sealing disk.Valve member 110 may be normally open and held in the open positionduring operation of valve 20 by an abutment structure indicatedgenerally at 114 that is secured to the upper housing 34. Other detailsof valve member 110 and the configurations of abutment structures 114that may be used are more fully discussed in U.S. Pat. Nos. 5,454,394;5,193,569; and 5,099,870 referenced previously, which disclose similarpoppet valve and abutment structures. Alternatively, valve member 110may be held in an open position during normal operation of valve 20 bythe pressure of the fuel flowing within valve 20. Valve member 110 maybe biased toward a closed position by a biasing member 116 that may, forexample, be a coil spring. In the closed position, the valve element 112is disposed in sealing engagement with a valve seat 118 formed in theupper housing 34. Valve member 110 may be forced closed by biasingmember 116 in the event of certain failure modes, as subsequentlydiscussed. Valve 20 may also optionally include a pressure relief valve(not shown) that can be disposed in a tubular stem 120 of valve member110. The features of relief valves that may be used are discussed in thepreviously referenced patents. In any event, the pressure relief featureprevents a large pressure build up in the piping above the valve 20 onthe occasion that the valve is sheared or separated.

Since the lower housing 32 of valve 20 is rigidly mounted within sump41, when a predetermined load or force 122 is exerted on the housing 30of valve 20 (shown as acting on upper housing 34, but load 122 couldalso act on lower housing 32) on either side of the weakened portion 94,either directly or indirectly, valve 20 can define a failure mode thatdepends on the value of force 122. The most common instance that maycreate a failure in the housing 30 is the inadvertent contact of a motorvehicle with the fuel dispensing unit 38 that houses pipe 42. However, afailure in housing 30 may result from any relative movement betweenportions of the housing 30 above and below weakened portion 94 caused byexternal forces including frost heave and other environmentalconditions. In one failure mode, the force 122 is not sufficient tocause a first portion 124 of the housing 30 to substantially completelyseparate from a second remainder portion 125 of housing 30 alongweakened portion 94 (valve shearing), but is sufficient to cause a crack126 or other distress in housing 30, indicated in exaggerated form inFIGS. 3B and 3C, to emanate from the weakened portion 94 whereby thefluid flow passage 54 is in fluid communication with the expansiblechamber 108 (valve cracking). Accordingly, in this failure mode, thestructural integrity of housing 30 is compromised to an extent whereinthe fuel flowing within passage 54 can escape from housing 30 throughthe weakened portion 94 and into the expansible chamber 108 under thefuel line pressure. This in turn causes the expansible member 100 toexpand outwardly as shown in FIGS. 3B and 3C, as a result of thepressurized fuel entering chamber 108. Since the expansible member 100is sealed to the upper housing 34, any fuel entering chamber 108 isretained therein, which prevents or reduces fuel from escaping from thevalve 20 and thereby reduces the likelihood of environmental spills andthe costs associated with the cleanup of such spills.

The protruding portion 92 of first link 76 may be disposed in relativelyclose proximity to the expansible member 100. Accordingly, when themember 100 expands outwardly, due to pressurized fuel enteringexpansible chamber 108, it contacts the protruding portion 92 of firstlink 76 so that first link 76 uncouples from at least one of the housing30 and the second link 86. In the illustrated embodiment, the proximalend 78 of first link 76 disengages from the pin 80 secured to housing 30as shown in FIGS. 3B and 3C so that first link 76 uncouples from housing30. In other embodiments, first link 76 may be uncoupled from secondlink 86 or from both housing 30 and second link 86. When first link 76is uncoupled from one or both of the housing 30 and second link 86,valve element 62 is unlatched from the open position and moves to theclosed position as shown in solid line in FIG. 3C and in phantom line inFIG. 4 due to the action of biasing member 72. When valve element 62 isin the closed position, fuel is prevented from flowing from the fluidinlet 50 to the fluid outlet 52. Instead, fuel entering inlet 50 aftervalve element 62 is closed is retained within lower housing 32, therebyavoiding or reducing the likelihood of fuel spillage externally ofhousing 30.

When force 122 has a relatively higher value, the weakened portion 94may define another failure mode (not shown herein) wherein the firstportion 124 of housing 30 separates substantially completely from thesecond portion 125 of housing 30. In this valve shearing failure mode,the expansible member 100 does not prevent or otherwise inhibit suchseparation of the first portion 124 of housing 30 from the secondportion 125 of the housing 30. Instead, the force 122 may cause theexpansible member 100 to disengage from the housing 30 in a manner thatpermits the separation of the first and second portions 124, 125. Theseparation of the valve housings that do not include the expansiblemember in accordance with the invention, such as member 100, but areotherwise similar to valve 20, are illustrated in the foregoingreferenced patents. In the event of this valve shearing failure mode,first link 76 would also be uncoupled from one or both of the housing 30and second link 86, such that valve element 62 would move to the closedposition under the action of biasing member 72 and the valve element 112of the poppet or check valve 110 would also move to the closed positionunder the action of biasing member 116. Accordingly, when the valveelement 42 moves to the closed position, fuel may be prevented fromflowing through the lower housing 32 and externally of valve 20. Also,any fuel contained within the pipe 42 may be prevented from backflowingthrough the upper housing 34 and externally of valve 20. Accordingly,the likelihood of fuel spillage externally of valve 20 would beprevented or reduced.

FIGS. 5, 6A and 6B, in which like reference numerals refer to likefeatures in FIGS. 1-4, illustrate a valve 130 according to anotherembodiment of the invention. Valve 130 includes a housing, or conduit,132 comprising an upper housing 134 and a lower housing 32. Upperhousing 134 may be removably secured to lower housing 32 by conventionalmeans such as fasteners 136. Again, while this embodiment is shown anddescribed as a two-part housing, the invention is not so limited as aone-piece housing may also be utilized. Housing 132 defines a fluidinlet 138, a fluid outlet 140 and a fluid flow passage 142 (FIGS. 6A and6B) extending between the fluid inlet 138 and the fluid outlet 140. Thefluid flow passage 142 may be suitable for the flow of pressurized fueltherein, such as fuel 24.

Valve 130 may further include an expansible member 144, in lieu ofexpansible member 100, that defines an expansible chamber 145 (FIG. 6B)and is disposed in surrounding relationship with a weakened, orfrangible, portion 146 formed in upper housing 134 and is sealed to theupper housing 134 at a first location 148 downstream of the weakenedportion 146 and at a second location 149 upstream of the weakenedportion 146. The weakened portion 146 may be a groove extending around aperimeter of upper housing 134 and may be generally V-shaped as shown inFIGS. 6A and 6B. The expansible member 144 may be a sleeve and may havea somewhat different configuration than the expansible member 100, asshown in FIGS. 6A and 6B. Expansible member 144 may be made of the sameelastomeric materials discussed previously with regard to expansiblemember 100.

Valve 130 may include a latching mechanism, indicated generally at 149,which releasably latches the valve element 62, disposed in the lowerhousing 32, in the open position. In the illustrated embodiment,latching mechanism 149 may be a linkage. However, latching mechanism 149may be other devices suitable for latching valve element 62 in the openposition. During normal operation of valve 130, i.e., not during afailure mode of valve 130, linkage 149 may be coupled to both valveelement 62 and housing 132. Linkage 149 may include a first link 150having a first link portion 152 that is pivotally coupled to housing132. The pivotal coupling of first link portion 152 to housing 132 maybe achieved by a pin 154, or like member, which extends through firstlink portion 152 into an embossment 156 secured to upper housing 134.The first link 150 may further include a second link portion 158 alsopivotally coupled to housing 132. In the illustrated embodiment, pin 154passes through both of the first and second link portions 152, 158 andinto embossment 156. Second link portion 158 includes a first arm 160pivotally coupled to pin 154, a second arm 162 coupled to the first arm160, and a third arm 164 that is coupled to second arm 162 and alsopivotally coupled to the upper housing 132. Second arm 162 extendsgenerally tangentially relative to upper housing 134 of housing 132proximate the expansible member 144. The pivotal coupling of third arm164 to housing 132 may be achieved by a pin 166, or like member, whichextends through third arm 164 into an embossment 168 secured to upperhousing 134. Pins 154 and 166 may be coaxially disposed so that firstand second link portions 152 and 158 pivot together about a centerlineaxis 170 of pins 154 and 166, which may be separate pins or can be madeas a one piece construction. Moreover, while second link portion 158 isshown and described as an integral member, i.e., the first, second andthird arms 160,162, and 164 are integrally formed, those of ordinaryskill in the art will recognize that the arms may be separate and thenassembled to form second link portion 158.

As best seen in FIGS. 6A and 6B, first link portion 152 may include anotch 180 formed therein. Linkage 149 further includes the second link86 as in valve 20 and discussed previously. Second link 86 may alsoinclude a pin 182 extending from second link 86 that is received in thenotch 180 of first link portion 152. A biasing member 184, which may bea spring coiled about pin 154, biases the first link portion 152 towarda position wherein pin 182 is engaged in notch 180. For instance, inFIGS. 6A and 6B, the spring biases first link portion 152 in thecounterclockwise position. In this position, valve element 62 of valve60, disposed in lower housing 32 and illustrated and discussedpreviously with regard to valve 20 (not shown in FIGS. 5-6B), is latchedin an open position.

Since the lower housing 32 of valve 130 is rigidly mounted within sump41, when a predetermined force 190 is exerted on the housing 132 ofvalve 130 (shown as acting on upper housing 134, but load 190 could alsoact on lower housing 32) on either side of the weakened portion 146either directly or indirectly, valve 130 can define a failure mode thatdepends on the value of force 190. The most common instance that maycreate a failure in housing 132 is the inadvertent contact of a motorvehicle with the fuel dispensing unit 38 that houses pipe 42. However, afailure in housing 132 may result from any relative movement betweenportions of the housing 132 above and below weakened portion 146 causedby external forces such as frost heave or other environmentalconditions. In one failure mode, the force 190 is not sufficient tocause the first portion 124 of housing 132 to substantially completelyseparate from the second remainder portion 125 of the housing 132 alongweakened portion 146 (valve shearing), but is sufficient to cause acrack 194 or other distress, indicated in exaggerated form in FIG. 6B,to emanate from the weakened portion 146 whereby the fluid flow passage142 is in fluid communication with the expansible chamber 145 (valvecracking). Accordingly, in this failure mode, the structural integrityof housing 30 is compromised to an extent wherein the fuel flowingwithin passage 142 can escape from housing 132 through the weakenedportion 146 and into the expansible chamber 145 under fuel linepressure. This in turn causes the expansible member 144 to expandoutwardly as shown in FIG. 6B, as a result of the pressurized fuelentering chamber 145. Since the expansible member 144 is sealed with theupper housing 134, any fuel entering chamber 145 may be retainedtherein, which may prevent or reduce the likelihood of fuel spillageexternally of valve 130.

The second arm 162 of second link portion 158 is disposed in relativelyclose proximity to the expansible member 144. Accordingly, when theexpansible member 144 expands outwardly, due to pressurized fuelentering expandsible chamber 145, it contacts second arm 162 so thatsecond link portion 158 rotates upwardly relative to the upper housing134 and about axis 170. Due to the connection at pin 154, first linkportion 152 rotates downwardly relative to upper housing 134 about axis170, thereby disengaging pin 182 from notch 180. This rotation of firstlink portion 152 uncouples the first link portion 152 from second link86, which is coupled to valve element 62 (shown and discussed previouslywith regard to valve 20; not shown in FIGS. 5, 6A and 6B). Accordingly,valve element 62 is unlatched from the open position and moves to aclosed position (shown previously with respect to valve 20) within thelower housing 32 due to the action of biasing member 72. When valveelement 62 is in the closed position, fuel is prevented from flowingfrom the fluid inlet 138 to the fluid outlet 140. Instead, fuel enteringinlet 138 after valve element 62 is closed is retained within lowerhousing 32. Accordingly, the likelihood of fuel spillage externally ofvalve 130 may be reduced or prevented.

In the illustrated embodiment, valve 130 does not include the poppet orcheck valve 110. However, this may be optionally included in otherembodiments. If poppet valve 110 is included, the poppet valve 110 maybe moved to a closed position, as discussed previously with regard tovalve 20 when a relatively larger predetermined load causes the housing132 to substantially completely separate. The expansible member 144 doesnot prevent or otherwise inhibit this separation of the housing 132.Linkage 149 is also uncoupled from valve element 66 in this valveshearing failure mode, so that valve element 62 moves to the closedposition under the action of biasing member 72. The poppet valve mayalso move to the closed position as discussed previously with respect tovalve 20, if incorporated in valve 130.

FIGS. 7 and 8, in which like reference numerals refer to like featuresin FIGS. 1-6, illustrate an emergency shutoff valve 200 according toanother embodiment of the invention. Valve 200 comprises a housing 210that includes the lower housing 32 as described for valves 20 and 130and discussed previously, and an upper housing 212 that may be removablysecured to the lower housing 32 by conventional means, such as bolts214. The housing 210 may be a one-piece construction instead of thetwo-part construction described herein. Housing 210 of valve 200 definesa fluid inlet 220, a fluid outlet 222 and a fluid flow passage 224extending between the fluid inlet 220 and the fluid outlet 222 as shownin FIG. 8. Fluid flow passage 224 may be suitable for the flow ofpressurized fuel therein, such as fuel 24.

As with valves 20 and 130, the shutoff valve 200 includes a valve member60 that can be a flapper or butterfly type valve that is movably mountedwithin the lower housing 32. Valve member 60 includes the valve element62 that is movable between an open position and a closed position asillustrated and discussed previously with respect to valve 20. Valveelement 62 may be biased toward a closed position by the biasing element72 as discussed previously with respect to valve 20. When valve element62 is in the closed position, fuel flow between fluid inlet 220 andfluid outlet 222 is prevented.

Shutoff valve 200 may include a latching mechanism indicated generallyat 229 in FIG. 7, which releasably latches valve element 62 in the openposition. In the illustrated embodiment, latching mechanism 229 may be alinkage. However, latching mechanism 230 may be other devices suitablefor latching valve element 62 in the open position. During normaloperation of valve 200, i.e., not during a failure mode of valve 200,linkage 229 may be coupled to both the valve element 62 and to housing210. Linkage 229 may include a first link 230 and may also include thesecond link 86, as in valves 20,130 and discussed previously, which iscoupled to valve element 62 in the same manner as discussed previouslywith respect to valve 20. First link 230 includes a proximal end coupledto housing 210. This can be accomplished by a pin 236 that passesthrough a proximal end of link 230 into an embossment 238 secured to theupper housing 212 of valve 200 as shown in the illustrated embodiment. Adistal end of first link 230 may be coupled to second link 86. This maybe accomplished by a pin 240 extending from the proximal end 84 ofsecond link 85 that passes through the distal end of first link 230 asshown in the illustrated embodiment. The first link 230 latches thevalve element 62 in an open position when the linkage 229 is coupled toboth housing 210 and valve element 66.

Housing 210 may include a weakened, or frangible, portion 242 formedtherein that is downstream of the valve element 62. In the illustratedembodiment, upper housing 212 may include the weakened portion 242formed therein, which extends circumferentially around a perimeter ofthe upper housing 212. The invention, however, is not so limited. Theweakened portion 242 may be a groove and may have an inner portion thatis generally V-shaped, as shown in FIG. 8. The weakened portion 242defines a predetermined fracture or failure site for various failuremodes as subsequently discussed.

Valve 200 may further include an annular member 246 that partiallycircumscribes the upper housing 212 and may be sealed to the upperhousing 212 at locations that are upstream and downstream of theweakened portion 242, which may be accomplished using O-rings 248, forexample. Annular member 246 may be made of a variety of materialsincluding plastics, metals and elastomeric materials. A hollowprotruding member 250 may be formed integral with the annular member 246and extends away from the upper housing 212. Valve 200 may furtherinclude an expansible member 252 that comprises a diaphragm in theillustrated embodiment that is disposed in sealing engagement with theprotruding member 250. An upper portion 253 of first link 230 isdisposed proximate the hollow protruding member 250. Expansible member252 may be made of an elastomeric material such as the materialsdiscussed previously with regard to the expansible member 100 of valve20. The expansible member may also be inelastic but be formable so as tooperate as a rolling diaphragm. Expansible member 252 defines at least aportion of an expansible chamber 254 that is disposed externally ofhousing 210, and more particularly is disposed externally of the upperhousing 212. The expansible chamber 254 includes at least the spacewithin the hollow protruding member 250 between the expansible member252 and the upper housing 212. Depending upon the properties of thematerial used to make the annular member 246, the expansible chamber 254may also include the space between the annular member 246 and the upperhousing 212, including the space between the weakened portion 242 andannular member 246.

Since the lower housing 32 of valve 200 is rigidly mounted with sump 41,when a predetermined force 270 is exerted on the housing 210 of valve200 on either side of the weakened portion 242, either directly orindirectly, valve 200 may define a failure mode that depends on thevalue of force 270. In one failure mode, the force 270 is not sufficientto cause a first portion 124 of housing 210 to substantially completelyseparate from a second remainder portion 125 of housing 210 alongweakened portion 242 (valve shearing), but is sufficient to cause acrack 274 or other distress emanating from the weakened portion 242,indicated in exaggerated form in FIG. 8. In this failure mode, the fluidflow passage 224 is in fluid communication with the expansible chamber254. Accordingly, in this failure mode, the structural integrity ofhousing 210 is compromised to an extent wherein the fuel flowing withinpassage 224 can escape from housing 210 through the weakened portion 242and into the expansible chamber 254 under fuel line pressure. This inturn causes the expansible member 252 to expand outwardly as shown inphantom line in FIG. 8, as a result of the pressurized fuel enteringchamber 254. Since the expansible member 252 is sealed to the upperhousing 212, fuel entering chamber 254 is retained therein, which mayprevent or reduce fuel from escaping from the upper housing 212externally of valve 200.

The first link 230 of linkage 229 is disposed in relatively closeproximity to the expansible member 252. Accordingly, when the expansiblemember 252 expands outwardly under fluid pressure it contacts first link230 so that first link 230 moves outwardly as shown in phantom line inFIG. 8 and is uncoupled from housing 210 and second link 86. In otherembodiments, it is possible for first link 230 to become uncoupled fromonly one of the housing 210 and second link 86. When first link 230 isuncoupled from one or both of the housing 210 and second link 86, valveelement 62 may be unlatched from the open position and moves to theclosed position, as discussed and illustrated previously with respect tovalve 20. When valve element 62 is in the closed position, fuel isprevented from flowing from the fluid inlet 220 to the fluid outlet 222.Instead, fuel entering inlet 220 after valve element 62 is closed may beretained within lower housing 32, thereby preventing or reducing thelikelihood of spillage of fuel externally of housing 210.

In the illustrated embodiment, valve 200 does not include the poppet orcheck valve 110 shown and discussed previously with regard to valve 20.However, valve 110 may be optionally included in other embodiments. Ifpoppet valve 110 is included, the poppet valve 110 may be moved to aclosed position, as discussed previously with regard to valve 20 whenthe load 270 has a relatively larger value, than that existing in thefirst failure mode, causing the first portion 124 of housing 210 tosubstantially completely separate from the second portion 125 of housing210. The annular member 246, protruding member 250 and expansible member252 do not significantly prevent such separation of the housing 210,i.e., they are not made of materials that would prevent such separation.In this event, the poppet valve 110 would move to the closed position asdiscussed previously, preventing or reducing the backflow of fuel fromthe dispensing unit through valve 110, thereby preventing or reducingthe likelihood of spillage external of valve 200. Additionally, thefirst link 230 would be uncoupled from one or both of housing 210 andsecond link 86 in this valve shearing failure mode as well, so thatvalve element 62 would move to the closed position and stop the flow offuel through valve 200.

FIG. 9 illustrates a valve 300 according to another embodiment of theinvention. The valve 300 is similar in construction and operation tovalve 20 shown in FIGS. 1-4 and described above, but for the inclusionof an access port 302. Accordingly, like reference numerals refer tolike features in FIGS. 1-4, and only the additional feature will bedescribed in detail. Moreover, although the access port 302 is shown anddescribed in connection with the valve shown in FIGS. 1-4, the accessport 302 may also be included in the valves shown in FIGS. 5-6B or FIGS.7-8 as well. As shown in FIG. 9, the access port 302 includes an inlet304, and outlet 306, and an open channel 308 extending between the inlet304 and outlet 306. In an advantageous aspect, the outlet 306 of theaccess port 302 is in fluid communication with the expansible chamber108 and the inlet 304 is accessible from outside of the valve 300. Theinlet 304 may include an enlarged bore 310 having internal threads thatcooperate with external threads on a removable plug 312 that fits withinbore 310 to seal the access port 302 in an air tight and liquid tightmanner. The plug 312 may include a bore, such as a hexagonal bore (notshown) in its outer surface 314 for engaging a tool (not shown) forrotating the plug 312 relative to the inlet 304 to engage/disengage theplug 312 therefrom.

The access port 302 provides a number of advantages to valve 300. Forexample, in one application the access port 302 may be used as a testport for checking the integrity of the expansible member 1 00 thatencompasses weakened portion 94. In such an application, a positive ornegative pressure generating device, such as a pressure pump or a vacuumpump, and shown schematically at 316, may be coupled to the inlet 304for generating positive or negative pressure within the expansiblechamber 108. Once the selected pressure is achieved in the expansiblechamber 108, the pressure will be monitored over a specified period oftime. To this end, the pressure generating device 314 may include apressure monitor for monitoring the pressure in the expansible chamber108 via the access port 302. Alternately, a separate pressure monitormay be operatively coupled to the inlet 304 for monitoring the pressure.

In any event, if the pressure in the expansible chamber 108 changes by athreshold amount over the selected time interval, such change may beindicative of a leak or tear in the expansible member 100. By way ofexample, the expansible chamber 108 may be positively pressurized(relative to atmosphere) up to pressure just under the pressure thatwould otherwise cause the valve to close. For example, the chamber 108may be pressurized up to approximately 5 psi. The pressure may then bemonitored for between approximately 20 seconds and 120 seconds. If thepressure drops or decreases by approximately 10% of the initial pressurethen a leak may exist in the expansible member 100 and it may bereplaced. In another embodiment, a negative pressure (relative toatmosphere) may be imposed in the expansible chamber 108 of up to 5 psivacuum pressure. The pressure may then be monitored for betweenapproximately 20 seconds and 120 seconds. If the pressure jumps orincreases by approximately 10% of the initial vacuum pressure then aleak may exist in the expansible member 100 and it may be replaced. Thetesting pressure, test time interval, and threshold pressure change maydepend on the specific application. Those of ordinary skill in the artwill appreciate that these values may be selected so as to detect a leakin the expansible member 100 or along the upper and lower seals to thehousing 30 with a relative high degree of accurracy.

The pressure check performed on the expansible member 100 may beconducted manually or by an automated control system normally associatedwith fuel dispensing systems, such as that shown in FIG. 1. Thus, in oneembodiment, a service station worker may access the valve 300 and removethe plug 314 from the inlet 304 as described above. The worker may thenuse a pressure generating device, such as a hand held device as isgenerally known in the art, to positively or negatively pressurize theexpansible chamber 108. The pressure within the chamber 108 may then bemonitored over a pre-determined time period. Once the test is completed,the plug 314 may be reinserted into inlet 304 and the access port 302sealed. If the pressure changes by the pre-determined threshold amount,the expansible member 100 may be replaced. Such a manual check may beperformed on the valve 330 at desired intervals. For example, thepressure checks may be performed daily, weekly, monthly, just a fewtimes a year, or at other desired time intervals.

In an alternate embodiment, the inlet 302 may be operatively coupled toa suitable pump, pressure monitor and other electronic control systemcomponents. These components may be already incorporated into the fueldispensing system and modified to conduct the pressure test, or thecomponents may be dedicated components specifically for performing thetests. At pre-determined time intervals (e.g., daily, weekly, monthly,yearly, etc), which may be input through the control, a pressure testmay be conducted and the results communicated to the control forprocessing. The control would determine if the threshold pressure changehas been reached within the time period for the test. If so, then thecontrol can notify an operator that the pressure test has failedindicating that the expansible member 100 should be replaced. Inaddition, the control may automatically shut down the fuel carryingconduit line until a successful pressure test is conducted.

In another application, the access port 302 may be used to facilitateassembly of the valve 300. For example, during assembly, and as theexpansible member 100 is being coupled to the housing 30 of the valve300, such as by the band clamps 106 or other straps, it may be desirableto remove the air from the expansible chamber 108. Thus, a vacuum pumpmay be coupled to the inlet 304 of access port 302 and a vacuum pulledto remove the air in chamber 108. In this way, the expansible member 100may be collapsed or sucked in toward the housing 30 so as to essentiallyfollow the contour of the housing 30. This minimizes the initial size ofthe expansible chamber 108 so that the valve 300 reacts more quickly toany crack or shear of the valve 300 as explained above. Pulling thevacuum during assembly may also allow for more reliable sealing of theexpansible member 100 to the housing 30 above and below the weakenedportion 94. In addition to these, the access port 302 may provide otheradvantages. For instance, as discussed below, the access port 302 mayprovide a path for inserting a self-expanding material into theexpansible chamber 108.

FIGS. 10A and 10B illustrate yet another embodiment of a shutoff valvein accordance with the invention. Valve 330 is similar in constructionand operation to valve 20 shown in FIGS. 1-4 and described above, butfor the inclusion of a self-expanding material disposed in theexpansible chamber 108. Accordingly, in these figures like referencenumerals refer to like features in FIGS. 1-4, and only the additionalfeature will be described in detail. Moreover, although theself-expanding material is shown and described in connection with thevalve shown in FIGS. 1-4, the material may also be included in thevalves shown in FIGS. 5-6B or FIGS. 7-8 as well. As shown in FIG. 10A,an expandable material 332 at least partially, and preferablycompletely, fills the expansible chamber 108. The expandable material332 is configured so that in a dry state, it has a first volume, and ina wet state it has a second volume greater than the first volume. Inother words, when at least a portion of the expandable material 332comes into contact with certain liquid mediums (e.g., fuels), such aswould occur if the valve 330 cracked, the material 332 would startexpanding.

In addition, the expandable material 332 may also be configured suchthat as the material 332 expands, it generates a sufficient pressurewithin the expansible chamber 108 to expand the expansible member 100outwardly. As explained above, as the expansible member 100 expandsoutwardly, it contacts the protruding portion 92 of first link 76 sothat first link 76 uncouples from at least one of the housing 30 and thesecond link 86 to move the valve element 62 to the closed position.Expandable materials which could operate as material 332 include but arenot limited to alkylstyrene copolymers, such as those available asImbiber Beads offered by Imbtech America, Inc. of Midland, Mich.Moreover, the expandable material 332 may be disposed in the expansiblechamber 108 during assembly thereof. Alternately, and as noted above,the expandable material 332 may be introduced into the expansiblechamber 108 through access port 302 on those embodiments incorporatingsuch an access port 302. In one embodiment, the expansible member 100and the expansible chamber 108 may be eliminated and the expandablematerial 332 disposed about the weakened portion 94, such as by bondingor other means known in the art, so as to close the valve on theoccasion the valve is cracked. Although in such an embodiment, fuel mayescape from the valve, the expandable material 332 is capable ofshutting down the valve thereby reducing the amount, if any, of fuelleaking to the environment.

Disposing expandable material 332 in expansible chamber 108 or aboutweakened portion 94 provides a number of advantages to valve 330. By wayof example, if the pressure in the conduit line, which operates as the“motive force” for shutting off the valve 20 described above, weresuddenly lost after the valve 330 were cracked or sheared, then theexpandable material 332 would provide the motive force for uncouplingthe first link 76 from the housing 30 and moving the valve element 62 tothe closed position. Thus, even under a lost pressure condition, thevalve 330 would be capable of shutting off and thereby prevent the flowof fuel through the valve 330. Another advantage provided by disposingmaterial 332 in expansible chamber 108 is to seal relatively small leaksin the expansible member 100 or leaks along the seals formed with thehousing 30 above and below the weakened portion 94. To this end, as thematerial 332 expands, small holes or openings in expansible member 100or along the upper and lower seals with housing 30 would becomepartially or completely occluded with the expanding material 332. Fuelthat would otherwise have escaped through the holes or openings has nowbeen prevented or reduced due to the presence of the expandable material332. Moreover, the expandable material 332 ensures that even in theevent of holes or openings in the expansible member 100 or along theupper and lower seals, which might otherwise prevent the expansiblemember 100 from actuating the valve member 60, the valve 330 will beshutoff due to the ability of the material 332 itself, and independentof the fuel conduit line pressure, to generate a sufficient pressure toactuate the valve member 60.

The various embodiments of the emergency shutoff valve as disclosedherein generally have a housing with a weakened portion and anexpansible member defining at least a portion of an expansible chamberin surrounding relationship to the weakened portion. The expansiblemember may be operatively coupled to a valve member in the shutoff valveto close the flow of fuel through the valve when the expansible memberis actuated. The valves disclosed herein provide certain advantages overexisting shear valves. In particular, in the unlikely situation of afailure mode that cracks the valve without substantially completelyshearing the valve, the valve according to embodiments of the inventionprevent or reduce the likelihood of fuel spillage that would otherwiseoccur with existing shutoff valves. In addition, this benefit isattained by using the fuel line pressure itself and/or the expansion ofa material in the expansible chamber or disposed about the weakenedportion as the motive force for closing off the valve in such a valvecracking failure mode. Thus, no additional energy or energy consumingcomponents must be supplied to the shutoff valve to actuate the valve toa closed position. The valves may include an access port that allows theexpansible member to be periodically tested or that facilitates assemblyof the valves. The shutoff valves according to the invention thenprovide additional benefits relative to conventional valves in a lowcost manner to achieve these benefits.

While the foregoing description has set forth various embodiments of thepresent invention in particular detail, it must be understood thatnumerous modifications, substitutions and changes can be undertakenwithout departing from the true spirit and scope of the presentinvention as defined by the ensuing claims. The invention is thereforenot limited to specific embodiments as described, but is only limited asdefined by the following claims.

1. An emergency shutoff valve for use in a fuel dispensing systemcomprising: a housing defining a fluid inlet, a fluid outlet and a fluidflow passage extending between said fluid inlet and said fluid outlet,said fluid flow passage being suitable for the flow of fuel therein; avalve element movable between an open position and a closed position,said closed position preventing fuel flow from said fluid inlet to saidfluid outlet; a latching mechanism coupled to said valve element, saidlatching mechanism releasably latching said valve element in said openposition; an expansible member defining at least a portion of a sealedexpansible chamber external of said housing; and an access port havingan inlet, an outlet, and a channel extending between said inlet andoutlet, said outlet in fluid communication with said expansible chamber,wherein said housing comprises a weakened portion disposed downstream ofsaid valve element, said expansible member being sealed to said housingat a first location upstream of said weakened portion and at a secondlocation downstream of said weakened portion; said emergency shutoffvalve defines a failure mode wherein the structural integrity of saidhousing is compromised to an extent wherein fuel can escape from saidhousing through said weakened portion and into said expansible chamberwhen a predetermined load is applied to said housing; and saidexpansible member is operable, upon occurrence of said failure mode, forreleasing said latching mechanism so that said valve element moves fromsaid open position to said closed position.
 2. An emergency shutoffvalve as recited in claim 1, further comprising: a removable pluginsertable into said inlet for sealing off the access port.
 3. Anemergency shutoff valve as recited in claim 1, further comprising: anexpandable material disposed in the expansible chamber.
 4. An emergencyshutoff valve as recited in claim 3, wherein said expandable material isan alkylstyrene copolymer.
 5. An emergency shutoff valve comprising: afluid conduit; a frangible area defined in said conduit; a valve memberoperably connected to said conduit upstream of said frangible area; anexpansible chamber, said frangible area being disposed in saidexpansible chamber; a movable member defining at least a portion of saidexpansible chamber; an access port having an inlet, an outlet, and achannel extending between said inlet and outlet, said outlet in fluidcommunication with said expansible chamber; and a linkage operablycoupled to said movable member and said valve member for shutting saidvalve upon movement of said movable member in response to leakage offluid through said frangible area.
 6. An emergency shutoff valve asrecited in claim 5, further comprising: a removable plug insertable intosaid inlet for sealing off the access port.
 7. An emergency shutoffvalve as recited in claim 5, further comprising: an expandable materialdisposed in the expansible chamber.
 8. An emergency shutoff valve asrecited in claim 7, wherein said expandable material is an alkylstyrenecopolymer.
 9. An emergency shutoff valve comprising: a housing having aweakened portion to define a predetermined failure site; and anexpandable material disposed about the weakened portion, wherein theexpandable material is capable of expanding from a first volume to asecond volume greater than the first volume.
 10. An emergency shutoffvalve as recited in claim 9, further comprising: an expansible member atleast partially surrounding said weakened portion to define anexpansible chamber therebetween, wherein the expandable material isdisposed in the expansible chamber.
 11. An emergency shutoff valve asrecited in claim 9, further comprising: a valve member, wherein saidexpandable material is operatively coupled to said valve member to closethe valve member when said expandable material is expanded to the secondvolume.
 12. An emergency shutoff valve as recited in claim 9, whereinthe expandable material expands from the first volume to the secondvolume when at least a portion of the material is contacted by a liquid.13. An emergency shutoff valve as recited in claim 9, wherein saidexpandable material is an alkylstyrene copolymer
 14. A method fortesting an emergency shutoff valve, comprising: providing an emergencyshutoff valve for use in a fuel dispensing system, the valve comprisinga housing with a weakened portion therein, an expansible member at leastpartially surrounding the weakened portion to define an expansiblechamber therebetween, and an access port in fluid communication with theexpansible chamber; pressurizing the expansible chamber using the accessport; and monitoring the pressure in the chamber after beingpressurized.
 15. The method as recited in claim 14, wherein the step ofpressurizing the expansible chamber includes positively or negativelypressurizing the chamber.
 16. The method as recited in claim 14, furthercomprising: determining the change in pressure within the chamber over aspecified period of time.
 17. The method as recited in claim 16, furthercomprising: replacing the expansible member if the change in pressurefrom the determining step exceeds a threshold value.
 18. The method asrecited in claim 14, wherein the recited steps are performed manually.19. The method as recited in claim 14, wherein the recited steps areperformed by a control system.
 20. A method of shutting off fuel flowingthrough a conduit defining a frangible area therein, said methodcomprising: defining an expansible chamber about the frangible area forcapturing fuel leaking through said area; disposing an expandablematerial at least partially within the chamber, the expandable materialcapable of expanding upon contact with fuel; and shutting off a fuelvalve in response to leaking fuel using at least in part the expansionof said expandable material.
 21. A method of shutting off fuel flowingthrough a conduit defining a frangible area therein, said methodcomprising: defining a chamber about the frangible area having anexpansible member forming at least a portion of the chamber; and usingthe expansion of an expandable material disposed in the chamber to shutoff fuel flow through the conduit.
 22. An emergency fuel flow shut-offvalve apparatus for shutting off the flow of fuel in a passage passingthrough the valve apparatus upon an application of force to a housing ofthe valve apparatus, the apparatus comprising: an expansible chamberdisposed bout an area of the housing predisposed to leak fuel upon theforce application to the housing, the leaking fuel changing the pressureacting on the chamber; and access means for monitoring the condition ofthe chamber.